This invention relates generally to improved toner compositions. More specifically the present invention relates to toner compositions including an externally situated performance additive or additives comprised of one or more specifically surface treated fumed silica particulate materials. Fumed silicas are known ultrafine silicon dioxide particulate materials that can have a variety of surface coatings thereover, and which particles and the selection of the coatings thereover can have a profound influence upon the toner and developer properties and performance characteristics. The present invention provides improved examples of surface treated fumed silica particulate materials and which materials can be readily be prepared and provide superior and unexpected toner charging properties, improved imaging processes and imaging apparatuses, and extended life-time of various imaging apparatus components, such as fuser rollers, and the like componentry utilizing the improved toner. The imaging processes of the present invention provide toners with high flow properties and stable A.sub.t properties that prevent or eliminate background deposits on the developed images, and effectively eliminate or minimize the detrimental so-called toner "charge through" phenomena. The imaging processes of the present invention provide working toners with an unimodal charge distribution, that is toners with little or no low charge or wrong sign toner as measured by a charge spectrograph. The imaging processes of the present invention provide toners that when fresh toner is dispensed into aged toner in a machine-throughput mode, little or no low charge or wrong sign toner is formed or remains in the working toner as measured by a charge spectrograph. The toner compositions of the present invention in embodiments thereof possess excellent admix characteristics, maintain their triboelectric charging characteristics for an extended number of imaging cycles, and enable the elimination or minimization of undesirable background deposits or spots on the imaging member or photoconductor, and the image receiver sheet or copy paper. Furthermore, the toner compositions of the present invention are substantially insensitive to relative humidity in a printing or copying machine environment and permit developed images with excellent optical densities and low background. Developers of the present invention are comprised of the toners and carrier particles, especially carrier particles comprised of a core with a mixture of polymers thereover. The toner and developer compositions of the present invention can be selected for electrophotographic imaging and printing processes, especially color processes and particularly digital processes.
The toner and developer compositions of the present invention can be selected for electrophotographic, especially xerographic, imaging and printing processes, including color, digital processes, and multicomponent systems apparatus and machines.